Production of Titanium

Abstract

A method of producing titanium semi-finished or ready-to-use products from titanium oxide powders and/or pellets is disclosed. The method produces products that are not affected adversely by levels of chlorine that have an impact on performance, particularly weldability, of products made by other methods.

1 . A method of producing titanium products comprising: 
 (a) electrochemically reducing titanium oxide in an electrolytic cell that includes an anode, a cathode, and a molten electrolyte that includes cations of a metal that is capable of chemically reducing titanium oxide and chloride anions; and    (b) processing the titanium product of step (a) and forming one of a semi-finished or ready-to-use product having a concentration of chlorine of at least 100 ppm.    
   
   
       2 . The method defined in  claim 1  wherein the titanium oxide is in the form of a powder or pellet.  
   
   
       3 . The method defined in  claim 2  wherein the titanium oxide powder or pellet has a size of 3.5 mm or less in a minor dimension of the powder or pellet.  
   
   
       4 . The method defined in  claim 2  wherein the size of the titanium oxide powder or pellet is less than 2.5 mm in the minor dimension of the powder or pellet.  
   
   
       5 . The method defined in  claim 2  wherein the size of the powder or pellet is 1-2 mm in the minor dimension of the powder or pellet.  
   
   
       6 . The method defined in  claim 1  wherein step (a) includes electrochemically reducing titanium oxide to titanium metal having a concentration of oxygen that is no more than 0.5% by weight.  
   
   
       7 . The method defined in  claim 6  wherein the oxygen concentration is no more than 0.3% by weight.  
   
   
       8 . The method defined in  claim 6  wherein the oxygen concentration is no more than 0.1% by weight.  
   
   
       9 . The method defined in  claim 1  wherein the electrolyte is a CaCl 2 -based electrolyte that includes CaO as one of the constituents.  
   
   
       10 . The method defined in  claim 1  wherein the electrolyte is a CaCl 2 -based electrolyte that includes CaO as one of the constituents and step (a) includes maintaining the cell potential above the decomposition potential for CaO.  
   
   
       11 . The method defined in  claim 1  wherein the electrolyte is a CaCl 2 -based electrolyte that includes CaO as one of the constituents and step (a) includes maintaining the cell potential below the decomposition potential for CaCl 2 .  
   
   
       12 . The method defined in  claim 1  wherein step (a) is carried out on a batch, continuous, or semi-continuous basis.  
   
   
       13 . The method defined in  claim 1  wherein the processing in step (b) includes quenching from an elevated temperature to a lower temperature at which there is a comparatively low rate of oxidation of titanium metal in air.  
   
   
       14 . The method defined in  claim 13  wherein the lower temperature is ambient temperature.  
   
   
       15 . The method defined in  claim 13  wherein the quenching is conducted with water.  
   
   
       16 . The method defined in  claim 2  wherein the forming includes compacting the titanium metal powder or pellet into a semi-finished or a ready-to-use product.  
   
   
       17 . The method defined in  claim 16  wherein, in a situation in which the semi-finished or ready-to-use product is a sheet, step (b) includes the steps of roll compacting the titanium metal powders or pellet into a strip, sintering the strip to increase the mechanical properties of the strip, and cold rolling the sintered strip into a sheet.  
   
   
       18 . The method defined in  claim 2  wherein step (b) includes processing the powder or pellet produced in step (a) by powder metallurgically processing the metal powder or pellet into a semi-finished or a ready-to-use product other than by roll compacting the powder or pellet.  
   
   
       19 . The method defined in  claim 1  wherein the semi-finished or ready-to-use product includes products in sheet, bar, or tube forms.  
   
   
       20 . A titanium metal semi-finished or ready-to-use product having a concentration of chlorine of at least 100 ppm produced by the method defined in  claim 1 .  
   
   
       21 . The titanium metal semi-finished or ready-to-use product defined in  claim 20  wherein the chlorine concentration is at least 200 ppm.  
   
   
       22 . The titanium metal semi-finished or ready-to-use product defined in  claim 20  wherein the chlorine concentration is at least 500 ppm.  
   
   
       23 . The titanium metal semi-finished or ready-to-use product defined in  claim 20  wherein the chlorine concentration is at least 1000 ppm.  
   
   
       24 . The titanium metal semi-finished or ready-to-use product defined in  claim 20  wherein the chlorine concentration is less than 2000 ppm.